powerpc/of: add eSPI controller dts bindings and DTS modification

Also modifiy the document of cell-index in SPI controller. Add the
SPI flash(s25fl128p01) support on p4080ds and mpc8536ds board.

Signed-off-by: Mingkai Hu <Mingkai.hu@freescale.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/arch/powerpc/boot/dts/p4080ds.dts b/arch/powerpc/boot/dts/p4080ds.dts
index 2f0de24..5b7fc29 100644
--- a/arch/powerpc/boot/dts/p4080ds.dts
+++ b/arch/powerpc/boot/dts/p4080ds.dts
@@ -236,22 +236,19 @@
 		};
 
 		spi@110000 {
-			cell-index = <0>;
 			#address-cells = <1>;
 			#size-cells = <0>;
-			compatible = "fsl,espi";
+			compatible = "fsl,p4080-espi", "fsl,mpc8536-espi";
 			reg = <0x110000 0x1000>;
 			interrupts = <53 0x2>;
 			interrupt-parent = <&mpic>;
-			espi,num-ss-bits = <4>;
-			mode = "cpu";
+			fsl,espi-num-chipselects = <4>;
 
-			fsl_m25p80@0 {
+			flash@0 {
 				#address-cells = <1>;
 				#size-cells = <1>;
-				compatible = "fsl,espi-flash";
+				compatible = "spansion,s25sl12801";
 				reg = <0>;
-				linux,modalias = "fsl_m25p80";
 				spi-max-frequency = <40000000>; /* input clock */
 				partition@u-boot {
 					label = "u-boot";